A professional diplomat and writer, Maurice Paléologue had already had considerable experience of diplomatic postings around the world as well as in the central administration in Paris when he was appointed ambassador to St. Petersburg just before the outbreak of war. He remained in this post until the 1917 March revolution and played an important role in consolidating the Franco-Russian alliance and in ensuring the most effective military effort from the ill-equipped Russian armies. His role in the 'July Crisis' of 1914 was critical. It was traditional that French ambassadors had much greater autonomy than in other European countries, and Paléologue was given ample opportunity to act as he saw fit between 24 and 29 July when both the French head of government and head of state were on the high seas returning to France from Russia. As the representative of Russia's only ally and recognised as having President Poincaré's support, Paléologue was peculiarly influential. By acting independently in two ways assuring Russia that it could count on unqualified French help in any pledges to Serbia, and failing to inform the Quai d'Orsay promptly of Russian mobilisation Paléologue could be said to have played an active role in encouraging Russia to opt for war. His motives were to ensure that the war which he saw as inevitable should come sooner rather than later, when French and Russian armies would be at a greater disadvantage vis-a-vis Germany. He also knew what the Germans proposed in the Schlieffen Plan because of his previous position in charge of secret files at the Quai d'Orsay. If the German plan of crushing France before turning to the eastern front was to be thwarted, Russian mobilisation had to be as rapid as possible. The view that Paléologue was acting as Poincaré's 'warmonger' has been challenged by recent research.
His account of the three years spent in Russia (La Russie des Tsars pendant la grande guerre, (Paris: Plon, 1922) provides an invaluable picture of the final years of the regime. He was replaced as ambassador by the Socialist Albert Thomas.